1. Field of the Invention
This invention relates to the field of linkless ammunition handling, using a storage drum or magazine with longitudinal rails holding inwardly directed rounds of ammunition and/or spent cartridge casings. More particularly, the invention relates to a method and apparatus for loading and unloading the rows of rounds in an ammunition drum of this type.
2. Prior Art
In magazines for feeding automatic and semi-automatic weapons, it has long been known to store rounds along longitudinal rails in a drum, the rounds facing radially inwardly, and means being provided to load and unload the rounds to and from the rails. U.S. Pat. No. 1,330,873-Hulse discloses a magazine wherein the rails are formed by wire-like elements, and the rounds are advanced by a central helix that pushes all the rounds in the entire drum simultaneously toward one end of the drum. This same type of device is used in connection with magazines for high rate of fire weapons and also for separately mobile transporting devices wherein the drum can be temporarily connected to an ammunition storage system in an aircraft, gun emplacement or the like, the transporter being used to load live rounds into the gun emplacement and to remove spent rounds, i.e., empty cartridge casings, therefrom.
A device for charging linked ammunition from a box into an aircraft is shown in U.S. Pat. No. 2,464,689-Jackson. A more modern apparatus wherein a storage drum is employed for loading and unloading is shown with several variations in U.S. Pat. Nos. 3,696,704-Backus, et al; 4,004,490-Dix et al; and, 4,005,633-Kirkpatrick. The storage drum is wheeled up to an aircraft and attached thereto as shown in Backus et al. The rounds are retained in longitudinal rails by means along the rails engaging the extractor flanges of the rounds as shown in Kirkpatrick. All the rounds are pushed along the rails by a central helix. An end-mounted means for transferring the slow longitudinal motion of the whole supply of rounds, into a faster circumferential motion for feeding the rounds to an external conveyor, is shown in Dix et al. The teachings of these patents are incorporated herein.
In a storage drum having longitudinal rails for retaining the rounds in rows, some means must be provided for moving the rounds down the rails to devices at one or both ends for transporting the rounds, chambering the rounds or otherwise handling them as needed. In the helix-type devices, the drum is held stationary and the helix is rotated to push the rounds along. While it is not necessary to move the drum, all the rounds must be moved at once, which is rather demanding in that all the rounds must be accelerated and decelerated when starting and stopping. Furthermore, contact between the helix and the individual rounds is not extensive or positive, and a jam caused for example by the extractor flange of a round catching in a longitudinal rail, can permanently deform the helix.
U.S. Pat. Nos. 4,127,055-Hottinger et al and 4,589,325-Muller et al relate to magazines for gun emplacements rather than to transport means for loading and unloading the gun emplacements. Nevertheless, the magazines are characterized by cylindrical storage-drums in which the rounds are held by their extractor flanges at a radially-inward orientation. In these patents the rounds are unloaded from the magazine in individual rows. Of course the objective is to have a continuous high speed stream of rounds being fed. Therefore, some means must be provided to accelerate and move a given row of rounds and to advance smoothly to the next row. In the Muller patent, the drum rotates continuously and a helical pushing device located externally of the drum engages a pushing tab that protrudes to engage the last round in the round-carrying rails. The external helix must follow a partly circumferential path while maintaining engagement between the pushing tab and the helix such that a complete row can be unloaded before rotation of the drum carries the pushing tab out of reach of the helix. Muller discloses a chain drive mechanism as an alternative to the helix. An endless chain conveyor has two tabs attached to links of the chain for pushing the rounds. Each tab is engageable behind an endmost round in a row. The chain is inclined relative to the drum axis and relative to the rails, whereby the pusher follows the path of an endmost round in the row as the round both advances along the rail and is carried around a certain angle of the drum's circumference due to rotation of the drum. This causes the pushing means for unloading the rails, e.g., the chain drive mechanism, to occupy the space of several rails of rounds. It is readily not possible to handle unloading and loading with the same pushing conveyor because the angle of inclination needed for loading is opposite the angle needed for unloading. Therefore, if two pushing conveyors were to be provided, one for loading and one for unloading, the pushing conveyors would occupy a substantial space and would present mechanical difficulties for a number of reasons including the fact that the pushing conveyors could not easily be arranged to follow the circumferential path of the rounds.
The present invention enjoys the advantages of a chain conveyor for moving individual rounds, but unlike the prior art arranges the conveyor chain on an indexing mechanism that allows the chain to be disposed parallel to the axis of the drum and parallel to each of the rows. Accordingly, loading and unloading can be accomplished in a narrow space, for example the space of three rows. The chain conveyors for loading and unloading are provided with a plurality of protruding pushing mechanisms, preferably one for every round in a row, reducing the incidence of jamming which otherwise could be caused by pushing a row of rounds from the endmost round in the row. The loading and unloading internal conveyor chains are placed directly within the drum in the area otherwise occuppied by the rounds. The internal conveyors are mounted with respect to the drum on arms aligned radially with respect to the drum axis. An indexing drive such as a cam means is provided to slowly advance the chain conveyors circumferentially in synchronism with the slow rotation of the drum until a complete row is loaded or unloaded, whereupon the drive halts the internal conveyor and simultaneously indexes the chain conveyor circumferentially to a next row, producing a continuous succession of rounds and returning a continuous succession of spent cartridge casings to the drum.